Electrical precipitator apparatus of the liquid spray type



5 Sheets-Sheet 1 F. V. PETERSON ELECTRICAL PRECIPITATOR APPARATUS OF THE LIQUID SPRAY TYPE v/ywwwwy w k\\\\\\\ lilllllli INVENTOR. FLOYD V. PETERSON July 18, 1967 F. v. PETERSON 3,331,192

ELECTRICAL PRECIPITATOR APPARATUS OF THE LIQUID SPRAY TYPE Original Filed Oct. 14, 1965 5 Sheets-Sheet 2 MAW i/i/li/l IN ENTOR.

FLOYD V PETERSON July 18, 1967 F. v. PETERSON 3,331,192

ELECTRICAL PRECIPITATOR APPARATUS OF THE LIQUID SPRAY TYPE Original Filed Oct. 14, 1963 5 Sheets-Sheet 3 27a mm Iii/MM g 2913 INVENTOR. F761 3 FLOYD V PETERSON July 18, 1967 v F. v. PETERSON ELECTRICAL PRECIPITATOR APPARATUS OF THE LIQUID SPRAY TYPE 5 Sheets-Sheet 4 Original Filed Oct. 14, 1963 INVENTOR.

FLOYD V. PETERSON July 18, 1967 F. v. PETERSON ELECTRICAL PRECIPITATOR APPARATUS OF THE LIQUID SPRAY TYPE Original Filed Oct. 14, 1965 5 Sheets-Sheet 5 INVEN TOR.

FLOYD V. PETERSON United States Patent 8 Claims. (Cl. 55-107) This application comprises a division of my co-pending patent application for Electrical Precipitator Apparatus of the Liquid Spray Type, Ser. No. 316,097, which was filed on Oct. 14, 1963, now abandoned.

Generally speaking, the present invention relates to electrical or electrostatic precipitators of the liquid spray type cooperable for removing particles of foreign or extraneous material from gas. More particularly, the present invention relates to improved precipitator apparatus of this general type adapted to remove particles of foreign or extraneous material, such as dust particles, suspended solids, foreign or undesired gases, or the like, from air or any other gas which is to be cleaned.

In a patent issued to me on Aug. 16, 1960, as US. Patent No. 2,949,168, covering Electrical Precipitator Apparatus of the Liquid Spray Type, I disclosed improved apparatus for the purpose of cleaning dust or other foreign or extraneous particles from gases.

In the present patent application I have disclosed apparatus which operates generally in accordance with the principles of the precipitator apparatus disclosed in my aforesaid patent and which has many of its advantages, but which also has additional advantages and certain advanced operating features.

Thus, an important object of this invention is to provide new and improved embodiments of electrical precipitator apparatus of the liquid spray type.

Another object of this invention is to provide improvements in certain of the operating features integrated with the precipitator system.

Another object of this invention is to provide for a certain degree of air cooling and controlled heating as well as air cleaning in connection with air conditioning in such precipitator apparatus.

Other and allied objects will become apparent to those skilled in the art after careful study of the present invention.

Thus this invention essentially covers improved apparatus for operation in conjunction with, or as a part of, precipitator systems which are in general comprised of the following component parts:

l) A gas duct means cooperable to transmit gas therethrough, including an input portion, a mixing portion having special inner and outer wall construction, and an output portion.

(2) First ionizing means located at the input portion of said gas duct means for the purpose of ionizing the foreign particles in the gas to be cleaned.

(3) A liquid spray chamber of special construction, with liquid spray heads located within or upon said spray chamber and with specially constructed second ionizing means located within spray chamber for ionizing the liquid spray which is dispersed into the mixing portion of said gas duct means.

(4) A fan or other arrangement for forcing or drawing the gas to be cleaned through said gas duct means.

(5) Means for condensing and draining away the commingled liquid spray and foreign particles.

(6) Power supply sources to provide the proper voltage to each of the two ionizing means.

(7) A liquid transmissive but electric current nonice transmissive path to ground for liquid that may be incidentally condensed in the precipitator mixing portion.

As set forth in my aforesaid Patent No. 2,949,168 referred to above, the provision of certain insulation between the discharging and non-discharging electrodes of the liquid spray ionizing means together with the specially constructed mixing portion and spray chamber, confine the power supplied to the liquid spray ionizing means to useful work within the precipitator enclosure, and precludes against undesirable voltage breakdowns and flashovers therein.

The spray liquid may be ordinary tap water which is suitable and desirable in most instances, although any spray liquid may be used unless unsuitable for such reasons as being rather explosive or too volatile.

FIGURES 1, 2, 3, 4, and 5, each show illustrative embodiments of the present invention with portions thereof in vertical section, with certain portions removed for clarity, and with certain portions in diagrammatic and/ or schematic form.

FIG. 1 is a view of one exemplary embodiment of the present invention with the gas duct means and spray chamber means thereof in longitudinal central section and with other associated portions of the apparatus being shown partially in electrical schematic form and partially in block diagrammatic form.

FIG. 1X is an enlarged sectional view through the spray chamber means taken in the direction of the arrows 1X1X of FIG. 1 showing the ionizing means in elevation and with all portions of the gas duct means behind the plane of the section removed for purposes of drawing simplification.

FIG. 2 is a fragmentary longitudinal sectional view generally similar to FIG. 1, but illustrating a modified form of the invention embodying a different type of spray chamber means.

FIG. 2X is a fragmentary longitudinal sectional view of the embodiment of the invention illustrated in FIG. 2 taken along a longitudinal plane substantially at right angles to the plane of the section comprising FIG. 2. This view also shows in fragmentary, partial-1y block diagrammatic and partially electrical schematic form certain associated elements of this modification of the invention.

FIG. 3 is a fragmentary longitudinal sectional view very similar to FIG. 2, but shows another modification of the invention having a different type of spray chamber means.

FIG. 3X is a fragmentary, enlarged, central sectional view of the specific embodiment of the modified spray chamber means shown in FIG. 3.

FIG. 3Y is a bottom plan view of another modification of the spray chamber means shown in FIGS. 3 and 3X, this modification being shown fragmentarily and in vertical section in FIG. 32.

FIG. 32 is a fragmentary, vertical sectional view of the modified form of spray chamber means illustrated in FIG. 3Y in bottom plan view.

FIG. 4 is a fragmentary longitudinal central sectional view generally similar to FIG. 1, but illustrating another modified form of the invention, and with a small portion of the channelled vertical insulating walls thereof shown in elevation and with the rest broken away for reasons of drawing simplification. This modification of the invention has a different type of spray chamber means which also has the above-mentioned liquid-transmissive but electric current non-transmissive channelled vertical insulating walls (shown in fragmentary form in this view and shown fragmentarily in cross-section in FIG. 4X).

FIG. 4X is a fragmentary cross-secti0n of one of the channelled vertical insulating walls of the modified precipitator shown in FIG. 4 (which is shown broken away in FIG. 4) taken in the plane indicated by the arrows 4X4X of the precipitator embodying the complete vertically channelled walls. In other words, FIG. 4X merely indicates the plane of the section as taken in a precipitator which does not have its vertical channelled walls broken away as shown in FIG. 4 for purposes of drawing simplification.

FIG. 4Y is a view generally similar to FIG. 1X, but with the walls of the spray chamber means removed for drawing simplification purposes. This view fragmentarily shows the modified ionizing means of FIG. 4 in elevation.

FIG. 4W is a fragmentary sectional view of another modified form of ionizing means and a portion of the spray chamber means mounting same viewed from the same position as the ionizing means shown in FIG. 4.

FIG. 4Z is a fragmentary sectional view similar to the bottom portion of FIG. 4 and illustrates a modified form of means for effectively insulating the suspended spray and foreign particles in the mixing chamber from the conductive material of the drain aperture.

FIG. 5 is a longitudinal sectional view very similar to FIG. 4, but illustrates a modified form of the invention with a different type of spray chamber means, a different type of condenser-type precipitator means, and a different type of liquid transmissive but electric current nontransmissive means to allow egress of condensed liquid and foreign particles from within the interior of the precipitator.

Referring to FIG. 1, a precipitator enclosure comprises four tubular sections or chambers: An input portion 1, a mixing portion 2, an output portion 4, and a spray chamber 3. A grounded electrically conductive shield or casing 5 generally encompasses the overall precipitator and constitutes the outer wall of the same. A conduit 6 generally comprises input portion 1. Portions 2 and 3 have inner linings 7 and 8 respectively, which are shown in FIG. l as being made of electrically conductive material. It should be understood that in certain forms of the invention, one of which is illustrated in FIG. 4, said inner linings may be made of electrical insulating material, as will be described more fully hereinafter.

In the FIG. 1 precipitator arrangement, the air or gas to be cleaned is forced through sections 1, 2, and 4 by the gas pressure at the input portion. However, said gas can also properly be drawn through the precipitator by a mechanical fan as indicated hereinafter for other embodiments of the precipitator, or drawn through the system by other suitable draft means.

The gas to be cleaned enters section 1 and passes through ionizing means 9 into mixing portion 2. The dust or foreign particles are electrically charged as they pass through ionizing means 9, which consists of dis charging electrodes 10 alternately spaced between nondischarging electrodes 11. A voltage is applied between electrodes 10 and 11 of about 10,000 volts DC. or more (depending upon electrical insulating conditions and electrode spacing) by means of power supply 10. The power supply connection is made to electrodes 10 by lead 12 which passes through insulator 13 located in recessed chamber 14; the other lead 15 being similarly connected (not shown in detail) between the power supply 10' and the non-discharging electrodes 11, which may be of the type shown in greater detail at 37 in FIG. 1X specifically illustrating the other ionizing means 21. As indicated, one end of chamber 14 is open and extends into the interior of the precipitator. The opposite end of chamber 14 is closed except for its opening into tube 16 which is attached thereto. A small blower or other suitable air pressure means, such as is indicated diagrammatically at 17, is used to force relatively clean air through tube 16 into container 14 and thence into mixing portion 2 at a relatively slow rate. The movement of the air around insulator 13 prevents moisture and debris from being deposited on it and thus aids in keeping said insulator clean and generally free of electrical flashovers.

Spray heads 18 located Within spray chamber 3 are supplied liquid through piping 19 from a source of liquid under pressure indicated diagrammatically at 20. The liquid spray emitted from spray heads 18 passes through ionizing means 21 where the spray droplets are electrically charged at a polarity opposite that of the dust or foreign particles, and the spray particles then pass into mixing portion 2.

A blower or other applicable air pressure means, such as is indicated diagrammatically at 22, is used to force air through tube 23 attached to cap 24, through perforations 25 provided in cover plate 26, and thence through spray chamber 3 into the mixing portion 2. This air movement helps carry the spray particles into said mixing portion. As an alternate method, the same results could be obtained by integrating an air jet with each spray head 18, similar to the arrangement used in the well known atomizing sprayer, in order to help disperse and carry the liquid spray into the mixing portion.

As the air or gas to be cleaned passes through section 2 the electrically charged foreign particles attach themselves to the oppositely charged spray droplets emitted from spray chamber 3, and are carried into output section 4. The spray droplets with the attached foreign particles strike against bafiie plates 27 and 28 in section 4 and are condensed and drained away through drain pipe 29.

Various means are provided to preclude against undesirable electrical flashovers within the precipitator enclosure, some of which are the same or similar to the means provided in the apparatus disclosed in my aforesaid Patent No. 2,949,168, referred to above. These include inner wall 7 of mixing chamber 2, inner wall 8 of spray chamber 3, and certain special construction features of ionizing means 21. Inner walls 7 and 8 are insulated and isolated from other portions of the precipitator by standoff insulators 30 and insulating material 31, which is equipped with small holes 32 for the ingress of clean air into section 2, to aid in keeping insulator material 31 clean on the inside of the precipitator. Cap 33 fits over insulating material 31 and around input portion 1, and the air is forced through holes 32 at a rather slow rate by means of a blower or other suitable air pressure means, such as is indicated diagrammatically at 34, connected to the tube 35.

Ionizing means 21 consists of alternately spaced discharging electrodes 36, and non-discharging electrodes 37 which comprise electrically conductive strips or rods 38 with electrical insulation 39 applied to the exterior surface thereof (see the plan view of ionizing means 21 shown in FIG. TX). The electrical isolation of said inner walls and the application of insulation 39 to electrodes 38, precludes against the ionized spray particles migrating to grounded parts of the precipitator and losing their charge thereon before they usefully perform their intended function in the precipitating action. Furthermore, the application of insulation 39 on the exterior surface of said non-discharging electrodes precludes against possible electrical flashovers in the spacial path between the discharging and non-discharging electrodes.

The lower portion of inner lining 7 is extruded and somewhat rippled, such as indicated at 40, or otherwise arranged to provide a drip means so that whatever liquid spray is condensed on the inside surface of inner lining 7 will be fairly well broken up and will fall in droplets a moderate distance in order to otter an electric current non-transmissive path to ground for such condensed liquid.

Power supply 41 supplies DC. voltage to ionizing means 21 at a voltage of about 10,000 volts or higher. The greater the voltage, within practical limits, the farther apart it is possible to space said discharging and nondischarging electrodes to produce an ionizing field of suitable intensity. Terminals 42 and 43 of power supply 41 are connected directly to the discharging and nondischarging electrodes of ionizing means 21 through leads 44, 45, and insulating bushing 46. A current limiting means 47 is connected in series with an electrical lead 48 which connects from ground to terminal 43 of power supply 41. With this arrangement, full operating voltage is applied across the electrodes of ionizing means 21 at all times to give best ionizing results, and at the same time the current supplied to the precipitator from power supply 41 is regulated by unit 47 to give more stable precipitator operation. Unit 47 may be a resistor, a vacuum tube current regulator or some other suitable current limiting means.

Voltage divider or potentiometer 49 is connected from terminal 42 of power supply 41 to ground, with its third terminal connected to inner lining 7 through insulating bushing 50. By means of adjusting the movable contact arm of the potentiometer 49, the inner lining 7 is electrically biased with respect to ground at a suitable voltage, which in general would be near or somewhat below that of discharging electrodes 36. This arrangement will help preclude against the electrically charged spray droplets migrating to said inner lining 7, since they hear an electrical charge of like polarity. Also, the potentiometer serves as a leakage path to ground for extraneous electrostatic charges occurring in the precipitator. Condenser 51 is a by-pass to ground for stray currents that might cause radio or video interference.

It should be noted that in cases where air or gas to be cleaned is drawn through a precipitator by suction applied to the output portion such as by a fan, or the like (such a fan being illustrated in FIGS. 2, 3, 4, and 5), the means for providing ingress of air to the ionizing means in the spray chamber means may be modified by eliminating the cap, tube, and blower or air pressure means, since air may be drawn through perforations, such as those shown at 25, by the action of such a suction fan in the output portion of the precipitator, thereby to aid in carrying spray particles into the mixing portion.

FIGURES 2 and 2X illustrate another embodiment of the present invention, which is generally similar to the FIG. 1 arrangement except for the location and construction of the spray chamber means.

Referring to FIGS. 2 and 2X, a precipitator gas duct means comprises three tubular sections or chambers: an input portion 1A, a mixing portion 2A, and an output portion 4A. A spray chamber 3A is located within section 2A in a manner so that chamber 3A is accessible from the opposite sides of mixing section 2A. A space is provided between the other two sides of spray chamber 3A and the inner lining 7A of mixing section 2A for the debris laden gas to pass.

A grounded electrically conductive shield or casing 5A generally encompasses the overall precipitator and constitutes the outer wall of the same.

As in FIGURE 1, the gas to be cleaned enters section 1A and the foreign particles are electrically charged as they pass through ionizing means 9A into mixing section 2A.

Spray heads 18A located within spray chamber 3A emit the liquid spray through ionizing means 21A and thence into mixing section 2A. Said liquid spray is electrically charged at a polarity opposite that of the foreign particles .as the spray passes through ionizing means 21A, which consists of an electrode arrangement similar to that shown at 21 and described in reference to FIGS. 1 and 1X.

The electrically charged foreign particles attach themselves to the oppositely charged spray droplets in mixing section 2A and the mingled spray and foreign particles are carried into output portion 4A. Therein they strike against baflle plates 27A and 28A and are condensed and drained away through drain pipe 29A. Like means are provided to preclude against undesirable selectrical flash-overs within the precipitator enclosure of FIGS. 2 and 2X as explained in reference to FIG. 1, except for the somewhat diiferent spray chamber arrangement. Mixing section 2A is provided with an inner lining 7A, and the liquid spray ionizing means 21A comprises discharging electrodes 36A, and non-discharging electrodes 37A insulated on the exterior surface, similar to the FIG. 1 arrangement.

Spray chamber 3A is provided with an open bottom wherein the spray ionizing means 21A is located. Said spray chamber has walls 8A comprised of electrical conductive material coated overall inside and out with electrical insulation. The conductive material of spray chamber 3A is electrically grounded outside the precipitator enclosure, as indicated. Spray heads 18A and spray means 52 are supplied liquid by piping 19A, which is comprised of electrical insulating material. Spray means 52 consists of an elongated enclosure with openings along its entire length for emitting a spray to keep the top of item 8A clean. Piping 19A is supplied liquid through liquid transmissive but electric current non-transmissive apparatus (not shown in FIGS. 2 and 2X, but of any suitable type, such as specifically disclosed in my Patent No. 2,949,168 referred to above and in Patent No. 3,098,890, issued to me on July 29, 1963, for Liquid Transmissive and Electric Current Non-Transmissive Apparatus).

A similar spray arrangement that is supplied liquid from such a liquid transmissive but electric current non transmissive source may be aptly used for cleaning other parts of the precipitator which are electrically isolated or which operate above ground potential. However, auxiliary cleaning means are generally not needed for most parts of the precipitator system.

The precipitator arrangement shown in FIGS. 2 and 2X has a drip means 40A provided on the lower part of inner lining 7A, electric power is supplied to the two ionizing means of the precipitator, and a current limiting means 47A is provided the same as item 47 described in reference to FIG. 1.

Inner lining 7A is comprised of electrically conductive material. Resistor 49A is connected from inner lining 7A to ground through insulator EtiA. Resistor 49A serves as a leakage path to ground for extraneous electrostatic charges that may occur within the precipitator. Condenser 51A serves as a by-pass to ground for possible radio or video interference resulting from the use of resistor 49A.

FIG. 3 shows another embodiment of the present invention wherein the gas duct means operates in the vertical position. In this embodiment, the precipitator enclosure is comprised of three sections or chambers: input portion 1B, mixing portion 22, and output portion 4B. A grounded electrically conductive shield or casing 5B generally encompasses the overall precipitator and constitutes the outer wall of the same. Mixing portion 23 is provided with inner lining 7B which is electrically insulated from other portions of the precipitator by means of stand-off insulators 30B and electrical sheet insulation 3113 provided with air ingress holes 32B.

The foreign particles in the gas stream are electrically charged by ionizing means 913 located Within input portion 1B.

Liquid spray particles are emitted from within sprayionizing means 3B (hereinafter described), and they are therein electrically charged at a polarity opposite to that of said foreign particles, and are thence dispersed into mixing portion 2B.

The oppositely charged spray and foreign particles combine in mixing portion 2B and the co-mingled particles are carried in the gas stream into output portion 4B, where said particles are condensed by striking against baflie plates 27B and 28B and are then drained away through drainpipe 29B.

Spray-ionizing means SE is a compact and effective arrangement for dispersing and electrically charging a liquid spray. FIG. 3X is an enlarged view, generally in cross-section, which depicts the various details of item 3B. Said spray-ionizing means comprises an outer shell or open end container 88 which is composed of electrical conductive material 53, coated overall with electrical insulation 54. A plate or support member 2613 is fastened within container 3B, as indicated. Discharging electrode assembly 55 and spray heads (or nozzles) 18B are mounted upon said member 26B. Container 8B serves a dual purpose of as a spray chamber and non-discharging electrode means. Discharging electrode assembly 55 consists of fine wire 36B wound on supporting form 56. Said fine wire 36B is electrically connected to spray heads 18B. Assembly 55 could also suitably comprise other types of discharging electrodes, such as a multiple arrangement of points or an array of sharp edged rings properly supported. About 10,000 volts DC. (or more depending upon the electrode spacing and electrical insulating characteristics) is applied across electrode means 55 and container 88 from power supply 41B, through metallic tubing 19B and conductor 45B, each of which is provided with electrical insulation on its exterior surface. Said applied voltage establishes an effective electrostatic ionizing field between discharging electrode means 55 and the inner wall of container 8B, which electrically charges the liquid spray particles as they are dispersed from spray heads 188 into mixing portion 2B. Spray liquid is supplied to spray heads 183 under pressure through tubing 19B, which in turn is supplied spray liquid through liquid transmissive but electric current non-transmissive apparatus (not shown, but of any suitable type, such as specifically disclosed in my above-identified patents). Tubing 23B is provided which is composed of electrical insulating material. This tubing supplies relatively clean air from outside the precipitator, which moves through openings 253 to the area around spray heads 18B and into mixing section 2B. Said air movement helps carry the spray particles into section 2B, which is especially desirable where the spray particles are relatively minute. Said air movement may result from the draft inside mixing portion 2B or from a blower or other pressure means applied to tubing 2313 outside the precipitator enclosure.

Recessed containers R and R with perforations P and P, respectively, are provided for keeping the insulation clean on tubing 19B and conductor 45B where they pass through the precipitator walls.

FIGS. 3Y and 3Z illustrate a spray-ionizing means of the same general type as indicated in FIG. 3X except with a more extensive electrode arrangement. Referring to FIGS. 3Y and 3Z, discharging electrode means 36C is spaced between the inner wall of container 8C, which serves as one non-discharging electrode, and the outer wall of cylinder 560, which serves as a second non-discharging electrode. Cylinder 56C is comprised of electrically conductive material coated overall with electrical insulation. It is electrically connected to container 8C by means of lead 57.

The FIG. 3 precipitator embodiment has a liquid drip means 4% provided on the lower part of inner lining 7B, and it is also provided with a current limiting means 47B, the same as item 47 described in reference to FIG. 1.

A leakage resistor 49B and by-pass condenser 51B are provided, which serve the same purposes as explained above in reference to FIG. 2.

FIGURE 4 shows a precipitator system in which the gas duct means operates in the horizontal position, with the spray chamber located above said duct means. The precipitator enclosure comprises four generally tubular sections or chambers, an input portion ID, a mixing portion 2D, an output portion 4D, and a spray chamber 3D. A grounded electrically conductive shield or casing D generally encompasses the overall precipitator and serves as its outer wall.

The foreign particles in the gas to be cleaned are electrically charged as they pass through ionizing means 9D, located within input portion 1D, and said particles combine with the oppositely charged spray particles in mixing section 2D. The co-mingled spray and foreign particles in the gas stream are then carried into output por tion 4D, where they are condensed and then drained away through drainpipe 29D located in the bottom of section 2D.

Voltage is applied to each of the ionizing means and a current limiting means 47D is provided the same as item 47 explained in reference to FIG. 1.

The new and novel embodiments of the FIG. 4 system include the manner of insulating the interior vertical walls of mixing section 2D and spray chamber 3D, also the method of providing an electrical insulating means at the bottom of mixing section 2D. There are two different methods described hereinafter for insulating the bottom of section 2D.

The interior of the vertical walls of sections 2D and 3D are lined with a specially designed electrical insulating material 56 except for the front wall of section 2D. The top and front walls of section 2D are composed of electrical sheet insulation 31D. Perforations 32D are provided in said front wall for the ingress of clean air to aid in keeping the interior of the insulation clean.

As indicated best in FIG. 4X, material 58 is channelled horizontally to provide a skirt insulator effect. After fabrication, the overall channelled surface has a material applied to it which has little affinity for the liquid spray used, such as certain silicone paints where the spray liquid is water.

Most spray liquids that are suitable in general for spray purposes (including ordinary tap water) will break up into droplets when running a short distance down a vertical wall lined with said channelled material, and the upper part of the channels at least will stay substantially dry. Thus material 58 provides an essentially electric current non-transmissive path between vertical points on such a wall, when said points are separated by at least a few channels, even with the condensed spray liquid running down the walls,

One method of providing an insulating means at the bottom of mixing section 2D is by laying a network of perforated pipe or closed channel 59 over the entire bottom surface if said section so relatively clean air is drawn through the perforations 60 in the pipe 59 from outside the precipitator. In case suitable draft is not available within the precipitator, a blower or other pressure means is used to force the air from the outside through said perforations in a manner similar to that described and illustrated hereinbefore.

The constant ingress of air into the bottom of mixing section 2D will maintain a layer of air which will serve as an electrical insulating layer between the bottom of section 2D and the gas stream which carries the suspended spray and foreign particles through the precipitator. Hence a liquid transmissive but electric current nontransmissive path is maintained between said gas stream and the bottom of section 2D.

FIGURE 4Z depicts an alternate method for providing an insulating means at the bottom of section 2E in lieu of controlled ingress of air. An array of battle plates 61 is provided as indicated, and is supported somewhat above the bottom of section 2E by insulation 31E at one end and by pedestal insulators 62 at several other points. The gas stream with the associated spray and foreign particles suspended therein will ride over plate assembly 61 as it passes to output portion 4E so that a liquid transmissive but electric current non-transmissive path is maintained between said gas stream and the bottom of mixing section 2E.

The co-mingled spray and foreign particles which are condensed in output portion 4E will drain back beneath piping 59 or plate assembly 61, whichever is used, over to drainpipe 29D or 29E located in sections 2D or 2E, respectively, where the conglomeration is drained away.

FIG. 4-Y is a sectional view through spray chamber 3D showing a plan view of ionizing means 21D, Said ionizing means consists of discharging electrodes 36D,

support insulators 63, through type insulator 64; non-discharging electrodes 37D consisting of conductive strips 38D provided with exterior insulation 39D; and framework 65 which has a recessed chamber 66 at each end provided with perforations 67. Said perforations allow the ingress of clean air to aid in keeping the electrode supports clean, In cases where the gas is forced through a precipitator enclosure so that the pressure is greater inside than outside the precipitator, caps may be placed over the openings such as perforations 67. Then clean air may be supplied to the caps through tubes from a blower or other suitable air pressure means and forced through said openings to aid in keeping the insulator supports clean.

FIG. 4W shows a cross-sectional view of another possible arrangement for ionizing means 21F. Discharging electrodes 36F consist of fine wires or other conventional type discharging electrodes alternately spaced between non-discharging electrodes 37F, which consist of metallic rods or plates. Strips of electrical insulation 68 are located between the discharging and non-discharging electrodes and run the full length of the same. Flow space is provided, as indicated, between the various electrodes and between the electrodes and insulating strips 68. Said strips 68 increase the length of the possibile electrical flashover path between the discharging and non-discharging electrodes, and thus help prevent flashovers between these electrodes. The insulating supports for the ends of the discharging and non-discharging electrodes and for insulating strips 63 may be kept clean by being located in recessed chambers similar to those depicted at 66 in FIG. 4Y.

Electrically charged spray particles will tend to collect upon the insulation 39D of the non-discharging electrodes 37D of the ionizing means 21D, or upon the insulating strips 68 where the alternate ionizing arrangement is used, such as shown in FIG. 4W, which will lower the ionizing efficiency of the ionizing means. There are many ways to offset this undesirable effect such as vibrating or rapping the electrodes and the insulating strip assemblies, blowing streams of air upon them, or coating said items with a material having low aifinity for the liquid spray used.

FIG. 4Y, referred to above, is typical also of the ionizing means 9D, which comprises discharging electrodes 10D, and non-discharging electrodes 11D, which are also provided with electrical insulation on the exterior surface. The common lead of electrodes 11D is connected to ground.

Spray heads 18D and 69 are each supplied spray liquid through separate liquid transmissive but electric current non-transmissive apparatus.

Spray head means 69 serve to keep ionizing apparatus 9D clean.

FIG. shows a further embodiment of the present invention together with certain apparatus used in connection with the system.

The FIG. 5 precipitator enclosure comprises five sections or chambers: input portion 1G, mixing portion 26, spray chamber 3G, output portion 4G, and discharge portion 70. A grounded electrically conductive casing 50 generally encompasses the overall precipitator and serves as its outer casing.

Ionizing means 9G, located in the input portion, may be any generally suitable means for ionizing foreign particles in a gas stream. Thus it is indicated as to approximate size and location only.

The spray and foreign particles are electrically charged, intermixed, and carried within the gas stream to output portion 46 the same as explained above in reference to the FIG. 4 arrangement.

A current limiting means 476 is provided which operates the same as 47 explained in reference to FIG. 1. In the FIG. 5 embodiment, inner lining 7G of mixing section 2G and inner lining 86 of spray chamber 3G are 10 composed of electrical conductive material. They are connected together and insulated from other portions of the precipitator by means of stand-off insulators 30G, and sheet insulation 316 which is provided with perforations 32G.

As disclosed in previously described embodiments of this invention, the liquid spray ionizing means 21G comprises discharging electrodes 36G alternately spaced between non-discharging electrodes 37G which are comprised of conductive strips 38G with exterior insulation 39G. The conductive strips 386 are electrically connected together outside of spray chamber 3G. Discharging electrodes 366 are spanned across spray chamber 3G and are connected to inner wall 8G of said chamber. Power supply 41G is connected to inner lining 8G by means of lead 446 which passes through insulator 46G. Condenser 71 is provided as a by-pass to ground for possible radio and video interference.

Since electrodes 36G, inner lining 7G, and inner lining 8G are all connected together and operate at the same applied voltage, a simplified arrangement is provided for the construction and connection of said items. This arrangement serves best where the operating voltage applied to the precipitator is not too high, such as in the neighborhood of 10,000 volts D.C.

Generally speaking, the same operating conditions can be obtained by biasing inner linings 7G and 8G at a somewhat lower voltage than is applied to discharging electrodes 36G. That is, by applying the voltage to said inner linings by some means such as a voltage divider arrangement, as described above in reference to FIG. 1. When using the lower biasing voltages, corona and extraneous electrical discharges are less liable to occur which may result from possible points, sharp edges and irregularities on inner linings 7G and 8G.

The bottom part of inner lining 7G is sloped to drain into liquid-debris discharge chamber 70. Thus the liquid which is condensed in section 26 runs along the bottom of said section and falls over drip edge 40G into chamber 70 where it is drained away through drainpipe 296. In the process of running over edge 40G and falling to the bottom of chamber 70, the liquid is broken up sufiiciently into droplets to offer an electric current non-transmissive path to ground from edge 406 to the bottom of chamber 70.

A new method is shown in output portion 4G for condensing the co-mingled spray and foreign particles from the gas stream. It consists of a multiple fan or rotating blade arrangement in which two or more sets of blades are used. As indicated, motor 72 drives blade set 73. Motor '74 drives blade sets 75 and 76. Motors 72 and 74 are connected to run in opposite directions. Blade sets 73 and 75 have blade pitches which will tend to force the gas stream back toward bafle plates 286, or at least beat into the gas stream as they rotate. Blade set 76 is a draft fan which could be replaced by other suitable draft means. It is provided with sufficient draft action to override the opposing action of blade sets 73 and 75 and still provide sufficient draft to draw the gas through the precipitator at the desired rate.

In operation, draft means 76 will draw the gas through the open spaces between blade sets 73 and 75 which will beat into the gas stream passing therethrough which carries the co-mingled spray and foreign particles. Considerable striking and wiping action is thus obtained on the suspended particles by the rotating blades which effectively condense said co-mingled particles.

There are many possible combinations for providing a suitable condensing arrangement using a draft means and striking blade means as discussed above. In general, it is well to alternate the direction of rotation of every other blade set means, whether they are used for draft or striking purposes. This will prevent certain of the blade sets from more or less following around rotating gas or air currents set in motion by preceding blade sets, and consequently doing little useful work. However, reversing the direction of rotation of every other blade set calls for a separate motor or some other individual driving means for each blade set, such as gears or belts, which in brief means more complicated equipment.

Also, it should be observed that the position of draft fan 76 might be interchanged with either striking blade set 73 or 75 in which case fan 76 would serve to force air between the blades of a striking fan in the condensing operation.

The spray liquid is supplied to spray heads 18G from liquid heating tank 77 through tubing 78 and tank assembly 20G. Tank means 206 provides a liquid transmissive path, but an electric current non-transmissive path from spray heads 186 to ground.

Tank 77 is supplied liquid through pipe line 79. The liquid is heated by means of burner 80 which is supplied fuel through pipe line 81. The fuel supply is controlled by means of control valve 82 connected in line 81. A temperature sensing device (not illustrated in detail since such are well known) may be connected with control valve 82 by means of line 83. Said sensing means may be a thermostat located in a room supplied air from the output of the subject precipitator, wherein the sensing means operates to modulate or shut off valve 82 by electrical or other control means when the temperature in the room reaches a predetermined point. On the other hand, control valve 82 may be controlled by a sensing means located in tank 77, which operates to modulate or cut off the fuel supply to burner 80 when the liquid in tank 77 reaches the required temperature.

A similar arrangement can be provided for controlling the temperature in a certain room or in tank 77 when using an electrical heating element in connection with the system instead of a fuel burner. In this case the temperature sensing means would serve to control the energy supplied to the heating element instead of controlling fuel to a burner.

The several precipitator embodiments disclosed herein by FIGS. 1, 2, 3, 4 and together with the associated views, are intended to depict certain possible variations in the precipitator system as a whole. The individual features indicated on the drawings do not necessarily apply only to the embodiment of the invention in which they are shown.

For instance the condensing arrangement shown in the output portion of the FIG. 5 system could just as well be applied to the precipitator systems indicated in FIGS. 1, 2, 3, and 4. The arrangement shown in FIG. 5 for providing controlled heating of the spray liquid could aptly apply to the other precipitator embodiments. A system in which the liquid spray chamber and ionizing means are located within the mixing section as shown in FIGS. 2 and 3 could be properly integrated with the other duct means arrangement of this invention. A sprayionizing means as illustrated in FIGS. 3X, 3Y, and 3Z could properly be located in the spray chamber of either the FIG. 1, 4, or 5 precipitator embodiment and thus replace ionizing means and the associated liquid spray means located in the spray chamber.

Numerous modifications and variations of the present invention will occur to those skilled in the art after a careful study thereof. All such, properly within the basic spirit and scope of the present invention are intended to be included and comprehended herein as fully as if specifically described, and illustrated and claimed herein.

The exact compositions, configurations, constructions, relative positionings, and cooperative relationships of the various component parts of the present invention are not critical, and can be modified substantially within the spirit of the present invention.

The embodiments of the present invention specifically described and illustrated herein are exemplary only, and

12. are not intended to limit the scope of the present invention, which is to be interpreted in the light of the prior art and the appended claims only, with due consideration for the doctrine of equivalents.

It should be noted that the present invention is directed to various embodiments of electrical precipitator apparatus in complete form and also to subcombinations thereof.

I claim:

1. An electric precipitator of the liquid spray type for removing foreign particles from gas, which includes a chamber having input and output ports and inner and outer walls with at least said inner wall being made of conductive material, means to cause said gas to flow through said chamber from said input to said output port, means associated with said input port for charging said foreign particles in said gas, means for generating a spray of relatively fine particles of liquid and causing said spray to co-mingle with said gas in said chamber, means associated with said spray means for charging said particles of liquid in opposite polarity as compared to the charge of said foreign particles in said gas, electrical insulating means between said inner and outer chamber walls, and means associated with said output port for condensing and precipitating the co-mingled mixture of said spray liquid and said foreign particles and for removing said mixture from said chamber, comprising the combination of: means for locating said means for generating and charging said spray liquid particles within the air path through said chamber, whereby the gas flow space is defined between said liquid particle generating and charging means, said liquid particle generating and charging means taking the form of a hollow conductive shell substantially closed on the end facing said input port and substantially open toward said output port, said conductive shell being further fully covered by a coating of electrical insulations; and means for applying an electrical bias to said inner wall of said chamber independently of the potentials of said outer Wall and said conductive shell of said liquid particle generating and charging means.

2. The invention set forth in claim 1 further defined in that said outer shell is of conductive material and is established at ground potential externally of said precipitator.

3. The invention set forth in claim 1 further defined in that said liquid particle generating and charging means has its conductive shell in the shape of a wedge within said chamber thereby to permit gas flow on two opposite sides of said wedge.

4. The invention set forth in claim 1 further defined in that means are provided for electrically biasing the said hollow conductive shell of said liquid particle generating and charging means while maintaining the electrical insulation of said shell with respect to other structural members.

5. The invention set forth in claim 1 further defined in that said inner chamber wall is truncated with respect to said outer wall in the direction in which gravity tends to make said liquid particles fall, and said inner wall is formed about the opening thereby produced in said inner wall, whereby liquid and foreign particle mixture running down said inner wall from condensed spray is broken into separated drops, on its way to said means for removing said mixture from said chamber, thereby to produce a liquid transmissive but electric current nontransmissive means.

6. The invention set forth in claim 1 further defined in that said means for generating said spray of liquid particles is fed by pumping means from the discharge of said condensing and precipitating means; heat exchanger means are provided; and means are included for passing said liquid thus returned through said heat exchanger on its way to said spray means, thereby to combine the ability to change the temperature of the said gas to be cleaned contemporaneously with the filtering action of said precipitator.

7. In an electric precipitator of the liquid spray type for removing foreign particles from gas, which includes a chamber through which gas to be cleaned is passed, means for changing said foreign particles by producing a strong electric field in an initial portion of the gas travel distance Within said chamber; means for generating a spray of liquid particles and co-mingling said liquid particles with said gas to 'be cleaned; means for charging said liquid particles in a polarity opposite to that of the said charged foreign particles by passing said liquid particles through a second strong electric field independent of said field for charging said foreign particles; high voltage sources connected to each of said electric field producing means; and current limiting means in series 14 with at least one of the connections for one of said electric field producing means and its corresponding high voltage source.

8. The invention set forth in claim 7 further defined in that said current limiting means comprises a resistor.

References Cited UNITED STATES PATENTS 8/1960 Peterson 55107 7/ 1966 Peterson.

ROBERT F. BURNETT, D. TALBERT,

Assistant Examiners. 

1. AN ELECTRIC PRECIPITATOR OF THE LIQUID SPRAY TYPE FOR REMOVING FOREGIN PARTICLES FROM GAS, WHICH INCLUDES A CHAMBER HAVING INPUT AND OUTPUT PORTS AND INNER AND OUTER WALLS WITH AT LEAST SAID INNER WALL BEING MADE OF CONDUCTIVE MATERIAL, MEANS TO CAUSE SAID GAS TO FLOW THROUGH SAID CHAMBER FROM SAID INPUT TO SAID OUTPUT PORT, MEANS ASSOCIATED WITH SAID INPUT PORT FOR CHARGING SAID FOREIGN PARTICLES IN SAID GAS, MEANS FOR GENERATING A SPRAY OF RELATIVELY FINE PARTICLES OF LIQUID AND CAUSING SAID SPRAY TO CO-MINGLE WITH SAID GAS IN SAID CHAMBER, MEANS ASSOCIATED WITH SAID SPRAY MEANS FOR CHARGING SAID PARTICLES OF LIQUID IN OPPOSITE POLARITY AS COMPARED TO THE CHARGE OF SAID FOREIGN PARTICLES IN SAID GAS, ELECTRICAL INSULATING MEANS BETWEEN SAID INNER AND OUTER CHAMBER WALLS, AND MEANS ASSOCIATED WITH SAID OUTPUT PORT FOR CONDENSING AND PRECIPITATING THE CO-MINGLED MIXTURE OF SAID SPRAY LIQUID AND SAID FOREIGN PARTICLES AND FOR REMOVING SAID MIXTURE FROM SAID CHAMBER, COMPRISING THE COMBINATION OF: MEANS FOR LOCATING SAID MEANS FOR GENERATING AND CHARGING SAID SPRAY LIQUID PARTICLES WITHIN THE AIR PATH THROUGH SAID CHAMBER, WHEREBY THE GAS FLOW SPACE IS DEFINED BETWEEN SAID LIQUID PARTICLE GENERATING SAID CHARGING MEANS, SAID LIQUID PARTICLE GENERATING AND CHARGING MEANS TAKING THE FORM OF A HOLLOW CONDUCTIVE SHELL SUBSTANTIALLY CLOSED ON THE END FACING SAID INPUT PORT AND SUBSTANTIALLY OPEN TOWARD SAID OUTPUT PORT, SAID CONDUCTIVE SHELL BEING FURTHER FULLY COVERED BY A COATING OF ELECTRICAL INSULATIONS; AND MEANS FOR APPLYING AN ELECTRICAL BIAS TO SAID INNER WALL OF SAID CHAMBER INDEPENDENTLY OF THE POTENTIALS OF SAID OUTER WALL OF AND SAID CONDUCTIVE SHELL OF SAID LIQUID PARTICLE GENERATING AND CHARGING MEANS. 